Blasting device



Junez'o, 1939.

A. J. TQMALIS BLASTING DEVICE Filed Deel 4, 1935 Invento'r gunnen,-

Attorney Patented June 20,- 1939 I'UNITED STATES PATENT OFFICEV 1 Claim.

This invention appertains to new and useful improvements in blastingswitches and more particularly to a switch employing a light vwhichserves to indicate when the circuit is properly functioning.

During the course of the following specification other important objectsand advantages of the invention will become apparent to the reader.

In the drawing: Figure 1 represents a side elevational view of theswitch with parts broken away.

Figure 2 represents a vertical sectional view through the switch takensubstantially on the,

' linev 2 2 of Figure l.

Figure 3 is a perspective view of one of the lamp contacts.

Figure 4 represents a perspective view of the other lamp contact.

Figure 5 is a diagrammatic view showing the electrical connection in andfrom the switch.

Referring to the drawing wherein like numerals designate like parts, itcan be seen that the switch consists of a block 5 of dielectric materialhaving the transverse bore 6 therein and also a vertically extendingbore 1. The vertically extending bore 'l .has a lampsocket 8 therein forreceiving a bulb 9. Numeral I Il represents a dielectric block' locatedin thev transverse bore 6 through which the stem II is slidable. Thisstem II extending through the large opening I2 in the lower portion ofthe contact strip I3, which strip I3 is provided with a laterallyextending contact 'portion I4 for engaging the center contact I5 of thebulb 9. The stem II has-a contact'head I5 there- Figure 2.

The opposite end of the stem I I projects beyond one side of the body 5and has a hand knob I1 thereon. Interposed between this knob I1 and thelower portion of the contact strip I8 is a coiled compressible spring I9which serves to maintain the stem II urged toward the left in Figure 2so as to maintain the contact head I 6 engaged with the co'ntact stripI3.

Rods 2I-22 extend downwardly through the body 5 at opposite sides of theblock I0. The lower end of the rod 22 is provided with a threaded bore23 for receiving the upper threaded end t portion of the pointed contactstrip 24. A jam "o nut and washer 25 is provided on the pin 24 and canbe jammed against the bottom of the body 5 to prevent self-adjustment ofthe pin 2l.r A strip 26 provided with a longitudinally extending slot 21therein has a depending pointed contact prong 28. A set screw-23 extendsthrough the slot 21 and is driven, into the threaded bre 30 in the lowerend of the rod 2|. The upper end of each of the rods 2I-22 is threadedto accommodate a conductor binding nut 3|. Extending from the rod 2| isa bus 32 which connects to the contact l strip I8 while abus strip 33extends from the rod 22 to engage the contact strip I3.

In the'useoi' this device, the switch is normally closed. This is thenormal position of the switch elements. Current will not flow along theconductors 35-35a until this switch is opened. However, to test thebattery land the switch above described, the shunt 20 with the lamp 9therein is employed and without the conductors 35-35a connected with theexplosive charge, by opening the switch I6 (see Figure 5) current willflow through this shunt and energize the lamp 9. This indicates that theswitching circuit is in operation. vThe prongs 24-28 are thendisconnectedvfrom the battery and the wires 35-35a connected with thecharge and the operator then takes the device to a remote point oi.safety and by applying the prongs 24-28 to the usual blasting batteryand pushing the button I1 so as to open the switch, the electric energysent along the circuit including the wires 35-35a, setting oi thecharge. However, as long as' the switch is closed the charge will not beset off and this obvi-l ously serves as a-sai'ety device.

Obviously if when the switch is opened and the light is energized andthe explosive is not set oif, the indication is that there is somethingwrong with the connection to the charge or in the conductors 35- 35a.

While the foregoing specification sets forth the invention in specicterms, it is to be understood that numerous changes in the shape, sizeand materials may be resorted to without departing from the spirit orscope of the invention as claimed hereinafter. V

Hating thus described the invention, claimed as new is:

A switch structure for blasting circuits com- `what is 'prising a bodyhaving a pair of battery engageable contact pins protruding therefrom, alamp on the body, a pair of binding posts on the body connected with thepins,.a switch mounted on the body, connections between the bindingposts and opposite sides of the switch, a shunt around said switch andhaving the lamp therein, a slotted member carrying one of the pins, ascrew disposed through the said slotted member and driven into one ofthe said'binding posts, said screw having the said slotted memberslidable thereon when the screw is unloosened with respect to itscorresponding bindingv post.

ANTHONY J. TOMALIS.

